The present invention relates to sprinklers for irrigation, and more particularly, to an irrigation sprinkler with a manually operable valve for selectively stopping the flow of water through an internal passage before it reaches the nozzle.
The climate in many parts of the world dictates the use of irrigation systems to maintain the desired vegetation. One system in widespread use with lawns, gardens, playing fields, golf courses and other forms of landscaping comprises a plurality of sprinklers connected to supply lines that branch off a water source. An electronic controller turns solenoid activated diaphragm valves on and off in accordance with a watering program to deliver water to blocks of sprinklers connected to the same supply line. One common type of sprinkler called a rotor has an outer cylindrical body with a pop-up riser and a replaceable nozzle. A turbine rotates the riser through an adjustable arc to distribute water over a predetermined sector at a preselected uniform precipitation rate. It is often desirable to change out a nozzle to one having a different precipitation rate or to adjust other features of the sprinkler. See for example U.S. Pat. No. 5,699,962 of Scott et al. granted Dec. 23, 1997 and entitled AUTOMATIC ENGAGEMENT NOZZLE, the entire disclosure of which is hereby incorporated by reference. Said patent is also assigned to Hunter Industries, Inc.
Normally the sprinkler must be off to replace the nozzle or perform other adjustments to the sprinkler. This requires that all of the sprinklers connected to a common supply line or branch line be shut off This in turn requires the maintenance worker to walk back and forth between the sprinkler and the diaphragm valve or controller. Alternatively, a helper can de-activate the valve for the particular line or manipulate the controller to shut off the zone that encompasses the sprinkler of interest. Either approach is tedious and inefficient. The diaphragm valve is often buried in a valve box and is difficult to access. Irrigation controllers often have complex controls and the simple turning off of a zone may be a bewildering operation that can result in permanent undesired alteration of the existing watering program.
In some situations it may be desirable to turn off the flow of water at one of a number of sprinklers all controlled by a common solenoid actuated valve. For example, it may be desirable to turn off one or more of several sprinklers in a zone for a number of days or weeks while a given area dries out from over-watering, while still permitting the other sprinklers in the same zone to turn on in accordance with the normal watering program.
It is preferable to turn off the sprinkler with an internal valve that is upstream of the nozzle while the water to the sprinkler is on rather than turning off the diaphragm valve or manipulating the controller. This is because the water pressure to the sprinkler is needed to extend the riser from the sprinkler body for easier access to the nozzle. If the water pressure to a pop-up rotor type sprinkler is turned off, the riser retracts under the force of a riser retraction spring. In this condition, only the top surface of the riser is visible, but the side of the riser is concealed. The removable nozzle is normally seated in a receptacle in the riser housing that opens on the side of the riser housing. Some pop-up rotor type sprinklers have slots or recesses in the top surface of the riser into which a tool may be inserted to manually pull the riser upwardly and out of the sprinkler body when the water pressure to the sprinkler is off. However, it is cumbersome to pull the riser out in this matter, and hold it extended while at the same time removing and replacing the nozzle from the side of the sprinkler body.
In designing a sprinkler with an internal flow stop valve there are certain practical constraints that limit the options available. For example, the valve should be manually operable from the top of the sprinkler. However, since the riser of a pop-up rotor contains a complex internal structure, there is very little space available for an internal valve. The valve must be located below the replaceable nozzle since the water must be shut off before the nozzle to allow the nozzle to be removed and replaced. This in turn necessitates the use of some sort of a linkage between the valve and the top of the sprinkler so that a tool can be used to manually turn the valve on and off. If the linkage intercepts the flow passage to the nozzle, a water-tight seal around the linkage is then required.
One sprinkler that has heretofore been designed to overcome the foregoing difficulties is disclosed in U.S. Pat. No. 5,762,270 of Kearby et al. granted Jun. 9, 1998 and entitled SPRINKLER UNIT WITH FLOW STOP. Said patent is also assigned to Hunter Industries, Inc. The sprinkler disclosed in said patent includes a valve in a passage leading to the nozzle which may be turned on and off by twisting a tool inserted in a slot in a cylindrical actuating member accessible from the top of the sprinkler. When the actuating member is rotated a spiral cam mechanism causes it to move axially in a vertical direction. This vertical motion is conveyed via an actuating rod to a circular valve body to move it into and out of engagement with a valve seat in a central water passage leading to the nozzle. The problem with this sprinkler is that there can be an excessive amount of flow resistance to water flowing through the passage and around the valve body to the nozzle when the valve is open. Additional flow resistance is generated by the shaft that extends through the water flow path and connects the actuating member and the circular valve body. This flow resistance has been found to adversely affect the spray pattern from the nozzle, such as by limiting the range or throw of the water stream ejected from the nozzle or otherwise degrading its spray pattern.
Accordingly, it would be desirable to provide an irrigation sprinkler with an improved internal manually operable flow stop valve that has less adverse impact on the hydrodynamic flow characteristics in the water flow path leading to the nozzle.